今天的两道题关于基本数据类型的探讨,估计也是要考虑各种情况,要细致学习 7. Reverse Integer Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 Have you thought about this? Here are some good questions to ask before coding. Bonus points for you if…

9. Palindrome Number Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the res…

[Q7]  把数倒过来 Given a 32-bit signed integer, reverse digits of an integer. Example 1: Input: 123 Output: 321 Example 2: Input: -123 Output: -321 Example 3: Input: 120 Output: 21 Solution: https://leetcode.com/problems/reverse-integer/discuss/229800/Pyt…

7 - Reverse digits of an integer. Example1: x = 123, return 321Example2: x = -123, return -321 Notice: 1.If the integer's last digit is 0, what should the output be? ie, cases such as 10, 100. 2.Did you notice that the reversed integer might overflow…

8. 字符串转换整数 (atoi) 8. String to Integer (atoi) 题目描述 LeetCode LeetCode8. String to Integer (atoi)中等 Java 实现 class Solution { public int myAtoi(String str) { if (str == null || str.trim().length() == 0) { return 0; } str = str.trim(); char firstChar = s…

这是悦乐书的第349次更新,第374篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Medium级别的第4题(顺位题号是8).实现将字符串转换为整数的atoi方法. 该函数首先去掉所需丢弃的空白字符,直到找到第一个非空白字符.然后,从该字符开始,采用可选的初始加号或减号,后跟尽可能多的数字,并将它们转换为整数. 字符串可以包含在形成整数之后的其他字符,这些字符将被忽略并且对此函数的行为没有影响. 如果str中的第一个非空白字符不是有效的整数,或者由于str是空的或者只包含空白字符而…

You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Note: Given n will be a positive integer. 对这种题目开始没有什么思路,借鉴博客http://blog.csdn.net/ken…

38. Count and Say The count-and-say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211, 111221, ... 1 is read off as "one 1" or 11. 11 is read off as "two 1s" or 21. 21 is read off as "one 2, then one 1&quo…

1. Two Sum Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution. Example: Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + n…

368. Largest Divisible Subset 题意:找到所有元素都不同的数组中满足以下规则的最大子集,规则为:子集中的任意两个元素a和b,满足a%b=0或者b%a=0. 解答:利用动态规划法求解.先给数组排好序.定义dp[i]表示以nums[i]结尾的子集的大小,则dp[i+1]=dp[j]+1,if nums[i+1]%nums[j]==0, 0<=j<=i,或者dp[i+1]=1.时间复杂度为O(n2). 代码如下: public List<Integer> la…